Let me try and explain this with a JAXR example . I am not sure what u meant by centralized .. can you clarify on that.
This is how I see it
ConnectionFactory factory = ConnectionFactory.newInstance();
//configure the ConnectionFactory
Properties props = new Properties();
props.setProperty(
"javax.xml.registry.lifeCycleManagerURL",
"https://uddi.ibm.com/testregistry/publishapi");
props.setProperty(
"javax.xml.registry.queryManagerURL",
"http://uddi.ibm.com/testregistry/inquiryapi");
props.setProperty(
"javax.xml.registry.registry.security.authenticationMethod",
"UDDI_GET_AUTHTOKEN");
factory.setProperties(props);
//Connect to UDDI
test registry
Connection connection = factory.createConnection();
The above code creates a single connection to only one inquiryapi or publishapi.
For a federated connection you can create connections to other sites for inquiry and publish api and combine them like below.
Collection fedCollection = new HashSet();
// Generally federated connections would involve more then two factory connections. Federated connections can help you combine a connection. you can create connections to different inquiryapis
fedCollection.add(connection1);
fedcollection.add(connection2);
FederatedConnection fedConn = factory.createFederatedConnection(fedCollection);
fedConn object lets you do all the calls you want which you do with a normal connection only now you have any number of sites interrelated.
I hope I didnt confuse you further.
HTH
Dhiren